Basic telephone services have been available for more than a century, but there is still a lot of room for improvement. One such area for improvement is the design of intelligent networks. Intelligent networks are networks which are flexible enough to be compatible and interoperable with other networks utilizing different standards. The advantages such intelligent networks would provide are the capability to offer desired features and functions more quickly, while minimizing the number of required hardware and software changes to network elements.
One of the most significant steps in the development of intelligent networks is the Signalling System 7 (SS7) standard. Signalling System 7 is a standardized packet network architecture that allows the interchange of call control information between switches and databases within and across communication networks.
Although international standards bodies approved Signalling System 7 in 1984, international networks are still far from intelligent or completely interoperable because they use different SS7 protocols and different types of global title addressing. For example, communication networks within North America (herein after collectively called the North American network) use the American National Standards Institute (ANSI) SS7 protocol, while networks outside North America (herein after collectively referred to as the foreign network) use the International Telecommunications Union (ITU) SS7 protocol. In addition, the North American network employs the International Mobile Station Identity (IMSI) type of global title addressing as defined by the International Telecommunications Union (ITU) Recommendation E.212. Whereas, the foreign network uses the Mobile Global Title (MGT) type of global title addressing as defined by ITU Recommendation E.214.
Thus, what is needed is an invention which increases the interoperability of international networks and, thus, allows roaming from one international network to the other.